Array substrate, method of fabricating array substrate, display panel, and method of fabricating display panel

ABSTRACT

The present disclosure generally relates to the field of display technology, and in particular, to an array substrate, a method of fabricating the array substrate, a display panel including the army substrate, and a method of fabricating the display panel. An array substrate includes: a base substrate; an electrode layer provided on the substrate; a first pixel defining layer on the electrode layer defining a plurality of pixel regions; and a second pixel defining layer on the first pixel defining layer, wherein the second pixel defining layer has a plurality of first grooves and a plurality of second grooves alternately arranged between two adjacent rows of pixel regions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the filing date of Chinese PatentApplication No. 201711354187.5 filed on Dec. 15, 2017 and Chinese PatentApplication No. 201710289732.0 filed on Apr. 27, 2017, the entiredisclosure of each of which is hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure generally relates to the field of displaytechnology, and in particular, to an array substrate, a method offabricating the array substrate, a display panel including the arraysubstrate, and a method of fabricating the display panel.

BACKGROUND

Organic light-emitting diode (OLED) display and liquid crystal display(LCD) are two of the most prevalent display devices in use today. OLEDoffers many advantages, including active light emission, highbrightness, high contrast, ultra-thin, low power consumption,flexibility and bendability, and tolerance over a broad range ofoperating temperatures. The numerous advantages that are possible withOLED makes it a highly competitive and developable candidate for thenext generation of display technology.

BRIEF SUMMARY

One embodiment of the present disclosure is an array substrate. Thearray substrate may comprise a base substrate; an electrode layer on thebase substrate; a first pixel defining layer on the electrode layerdefining a plurality of pixel regions arranged in an array of at least afirst color and a second color, the second color being different fromthe first color; and a second pixel defining layer on the first pixeldefining layer having a plurality of first grooves and a plurality ofsecond grooves alternately arranged between two adjacent rows of pixelregions. Each of the plurality of first grooves may have at least onefirst opening connecting the each of the plurality of first grooves to apixel region of the first color. Each of the plurality of second groovesmay have at least one second opening connecting the each of theplurality of second grooves to a pixel region of the second color.

In at least some embodiments, the plurality of first grooves in twoadjacent rows may be staggered with respect to each other along a rowdirection. The plurality of first grooves in two adjacent rows may bestaggered by a distance substantially equal to a width of one pixelregion along the row direction.

In at least some embodiments, the plurality of second grooves in twoadjacent rows may be staggered with respect to each other along a rowdirection. The plurality of second grooves in two adjacent rows may bestaggered by a distance substantially equal to a width of two pixelregions along the row direction.

In at least some embodiments, the second pixel defining layer mayfurther comprise a plurality of raised portions, each of the pluralityof raised portions being positioned to separate each of the plurality offirst grooves from an adjacent second groove.

In at least some embodiments, the first color may comprise two differentcolors. The plurality of first grooves in two adjacent rows may beconnected to the two different colors.

In at least some embodiments, a combined thickness of the first pixeldefining layer and the second pixel defining layer may be in the rangeof about 1.2 μm to about 2.5 μm. In other embodiments, a combinedthickness of the first pixel defining layer and the second pixeldefining layer may be in the range of about 1.5 μm to about 5 μm.

In at least some embodiments, each of the plurality of first groovesdoes not penetrate the second pixel defining layer. In otherembodiments, each of the plurality of first grooves may penetrate thesecond pixel defining layer.

In at least some embodiments, a width of each of the plurality of firstgrooves in a row direction may be about five times larger than a widthof each of the plurality of second grooves in the row direction.

In at least some embodiments, each of the plurality of second groovesmay comprise a first wall separating the second groove from an adjacentfirst groove, and a second wall separating the second groove from anadjacent pixel region of the second color. the at least one secondopening may be formed in the second wall, and has a width in a rowdirection that is smaller than a width of the second wall in the rowdirection.

Another embodiment of the present disclosure is a display panel. Thedisplay panel may comprise an array substrate as described above, and alight-emitting layer formed in the plurality of pixel regions.

Another embodiment of the present disclosure is a method of fabricatingan array substrate. The method may comprise forming the electrode layeron the base substrate; forming the first pixel defining layer on theelectrode layer; and forming the second pixel defining layer on thefirst pixel defining layer. The second pixel defining layer may have theplurality of first grooves and the plurality of second grooves.

In at least some embodiments, the step of forming the first pixeldefining layer may comprise depositing a first pixel defining film onthe electrode layer; and patterning the first pixel defining film intothe first pixel defining layer. The step of forming the second pixeldefining layer may comprise depositing a second pixel defining film onthe first pixel defining layer; and patterning the second pixel definingfilm into the second pixel defining layer.

In at least some embodiments, the first pixel defining layer and thesecond pixel defining layer are formed in a single patterning step. Thesingle patterning step may comprise depositing a first pixel definingfilm on the electrode layer; depositing a second pixel defining film onthe first pixel defining film; and patterning the first pixel definingfilm and the second pixel defining film simultaneously to form the firstpixel defining layer and the second pixel defining layer.

Another embodiment of the present disclosure is a method of fabricatinga display panel. The method may comprise providing an array substrate asdescribed above; dripping a first light emitting material into theplurality of first grooves; and dripping a second light emittingmaterial into the plurality of second grooves.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter that is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other objects, features, andadvantages of the present disclosure are apparent from the followingdetailed description taken in conjunction with the accompanying drawingsin which:

FIG. 1 shows a schematic diagram of an array substrate according to anembodiment of the present disclosure;

FIG. 2A shows a cross-sectional view of the array substrate exemplifiedin FIG. 1 along the section line A-A′;

FIG. 2B shows a schematic diagram of an array substrate according to anembodiment of the present disclosure;

FIG. 2C shows a cross-sectional view of the array substrate exemplifiedin FIG. 2B along the section line A-A′; FIG. 3A shows a cross-sectionalview of the array substrate exemplified in FIG. 1 along the section lineB-B′;

FIG. 3B shows a cross-sectional view of the array substrate exemplifiedin FIG. 2B along the section line B-B′;

FIG. 4A shows a cross-sectional view of the array substrate exemplifiedin FIG. 1 along the section line C-C′;

FIG. 4B shows a cross-sectional view of the array substrate exemplifiedin FIG. 2B along the section line C-C′;

FIG. 5 shows a schematic diagram of an array substrate according toanother embodiment of the present disclosure;

FIG. 6 shows a cross-sectional view of the array substrate exemplifiedin FIG. 5 along the section line D-D′;

FIG. 7 shows a cross-sectional view of the array substrate exemplifiedin FIG. 5 along the section line E-E′;

FIG. 8 shows a flow diagram of a method of fabricating an arraysubstrate according to an embodiment of the present disclosure; and

FIG. 9 shows a flow diagram of a method of fabricating a display panelaccording to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Next, the embodiments of the present disclosure will be describedclearly and concretely in conjunction with the accompanying drawings,which are described briefly above. The subject matter of the presentdisclosure is described with specificity to meet statutory requirements.However, the description itself is not intended to limit the scope ofthis disclosure. Rather, the inventors contemplate that the claimedsubject matter might also be embodied in other ways, to includedifferent steps or elements similar to the ones described in thisdocument, in conjunction with other present or future technologies.

While the present technology has been described in connection with theembodiments of the various figures, it is to be understood that othersimilar embodiments may be used or modifications and additions may bemade to the described embodiments for performing the same function ofthe present technology without deviating therefrom. Therefore, thepresent technology should not be limited to any single embodiment, butrather should be construed in breadth and scope in accordance with theappended claims. In addition, all other embodiments obtained by one ofordinary skill in the art based on embodiments described in thisdocument are considered to be within the scope of this disclosure.

An OLED display panel generally includes an array substrate and a coverlayer. OLED pixel units are formed on the array substrate, and the coverlayer is formed on the pixel units. Each OLED pixel unit generallyincludes an electrode, an organic thin film layer, and another electrodesequentially disposed on the array substrate. The organic thin filmlayer mainly includes a hole injection layer, a hole transport layer, anorganic light-emitting layer, and an electron transport layer stacked onthe electrode.

An OLED may be divided into two types—a bottom-emitting type and atop-emitting type, depending on the direction of emergent light. Abottom-emitting OLED (BEOLED) generally includes a cathode, an electrontransport layer, a light emitting layer, a hole transport layer, atransparent anode, and a substrate arranged sequentially in atransmission direction of light. Indium tin oxide (ITO) is generallyused in the transparent anode, and light exits from a side of the OLEDwhere the substrate is located, on which substrate the ITO material isprovided. Such an OLED is therefore referred to as a bottom-emittingOLED. On the other hand, a top-emitting OLED (TEOLED) generally includesa cathode, an electron transport layer, a light emitting layer, a holetransport layer, a reflective anode, and a substrate arrangedsequentially in the reverse transmission direction of the light. Lightexits from a side of the OLED where the cathode is located, so as to bereferred as a top-emitting OLED.

An OLED pixel unit is manufactured generally in one of two ways: thefirst is by vapor deposition, and the second is by inkjet printing.Vapor deposition allows the production of a full-color OLED product, andcan generate extremely high resolution, but material utilization is low.Further, to produce a large-size display, a white OLED (i.e., the WRGB(white, red, green, and blue) method) must be employed. On the otherhand, during inkjet printing, ink (for example, composed of a liquidorganic material) is uniformly deposited to form an organic thin filmlayer. Inkjet printing allows a high material utilization rate and canproduce large-size full-color display panels.

However, conventional inkjet printing technology, and its application tothe production of LED display panels, is not without limitations. Forexample, it is generally difficult to obtain high-resolution when usingconventional inkjet printing technology to print small and medium sizes,due to limitations in the volume of the ink droplets and printingaccuracy. Further, the instability of the conventional inkjet printingapparatus also generally makes the printing process difficult. Thus,there is a need to significantly improve the conventional inkjetprinting technology, for example, in order to increase print resolution.

An apparatus for ink jet printing generally in a plurality of nozzlesarranged side by side. Each area corresponding to a sub-pixel is alignedwith a nozzle, and during printing, the nozzles move and dispense ink toform the sub-pixels. More particularly, after printing a row ofsub-pixels, the nozzles are moved and repositioned to print the next rowof sub-pixels, and after each repositioning, the nozzles dispense ink.For products with a larger number of pixels per inch (PPI), the numberof ink dispensing operations that each nozzle must perform increases.This operation on a larger scale can be problematic in terms of controlof the nozzles on the one hand, and control of the uniform size of theink droplets during successive dispensing of the ink on the other.

Embodiments of the present disclosure utilize a double-layer structurefor the pixel defining layers. A first pixel defining layer comprising aplurality of pixel regions is provided on a substrate. A second pixeldefining layer is formed on the first pixel defining layer at a positionbetween two adjacent rows of pixel regions. The second pixel defininglayer has a plurality of first grooves and a plurality of secondgrooves. The first grooves and the second grooves are arranged in analternating manner. A first opening is provided on at least one portionof a first groove adjacent to a pixel region of a first color. The firstopening is configured to connect a plurality of pixel regions of thefirst color with the first groove. A second opening is provided on atleast one portion of a second groove adjacent to a pixel region of asecond color. The second opening is configured to connect a plurality ofpixel regions of the second color with the second groove. The firstcolor and the second color are different. When using inkjet printing toform the array substrate, light emitting materials are dispensed by theprinter nozzles directly into the first and second grooves. Moreparticularly, a light emitting material of the first color is directlydeposited into the first groove, and the flows into the correspondingpixel regions that are connected to the first groove via the firstopening. A light emitting material of the second color is deposited intothe second groove, and flows into the corresponding pixel regions thatare connected to the second groove via the second opening. Thedouble-layer structure of the pixel defining layers makes is possible tosimultaneously print light emitting layers in adjacent rows of pixelregions. An advantage of the embodiments of the present disclosure isthat, without making extensive, wholesale modifications to existinginkjet printing equipment, print resolution can be significantlyimproved, and the ease of operating the inkjet printing equipment can befacilitated.

FIG. 1 shows a schematic diagram of an array substrate according to anembodiment of the present disclosure. FIG. 2 shows a cross-sectionalview of the array substrate illustrated in FIG. 1 along the section lineA-A′. FIG. 3A shows a cross-sectional view of the array substrateillustrated in FIG. 1 along the section line B-B′. FIG. 3B shows across-sectional view of the array substrate exemplified in FIG. 2B alongthe section line B-B′;

As shown in FIGS. 1 to 3, the array substrate comprises a base substrate100, an electrode layer 101 formed on the base substrate 101, and afirst pixel defining layer 102 formed on the base substrate 101. Thefirst pixel defining layer 102 comprises a plurality of pixel regions103 arranged in a plurality of rows, so that in a top view (for example,as shown in FIG. 1) of the array substrate, the base substrate 100 looksto be subdivided into a plurality of pixel regions. The first pixeldefining layer comprises a plurality of first pixel defining portionsprovided between adjacent rows of pixel regions. The first pixeldefining portions are thus arranged into a plurality of rows, each rowbeing positioned between adjacent rows of pixel regions, for example, asshown in FIG. 1. The first pixel defining layer 102 has a thickness ofabout 0.3 μm to about 0.8 μm.

A second pixel defining layer 104 is formed on the first pixel defininglayer 102. More particularly, the second pixel defining layer 104comprises a plurality of second pixel defining portions that are formedon the first pixel defining portions at the position between adjacentrows of pixel regions. The second pixel defining portions are thusarranged into a plurality of rows, each row being positioned betweenadjacent rows of pixel regions, for example, as shown in FIG. 1. Thesecond pixel defining layer 104 has a thickness of about 1.5 μm to about2 μm.

In a top-emitting OLED (TEOLED), the cathode is generally configured tobe thin. If the first pixel defining layer and the second pixel defininglayer are made too thick, there is the risk of breakage in the cathode.The combined thickness of the first pixel defining layer and the secondpixel defining layer is in the range of about 1.2 μm to about 2.5 μm.The combined thickness of the first pixel defining layer and the secondpixel defining layer measures the vertical distance from the bottomsurface of the first pixel defining layer to the top surface of thesecond pixel defining layer. In some embodiments, a ratio of thethickness of the first pixel defining layer to the thickness of thesecond pixel defining layer is in the range of 1:3 to 1:4.

On the other hand, in a bottom-emitting OLED (BEOLED), the cathode isgenerally configured to be thicker than in a TEOLED. The combinedthickness of the first pixel defining layer and the second pixeldefining layer is in the range of about 1.5 μm to about 5 μm. Thecombined thickness of the first pixel defining layer and the secondpixel defining layer measures the vertical distance from the bottomsurface of the first pixel defining layer to the top surface of thesecond pixel defining layer. In some embodiments, a ratio of thethickness of the first pixel defining layer to the thickness of thesecond pixel defining layer is in the range of 1:3 to 1:4.

The second pixel defining layer 104 comprises a plurality of firstgrooves 111 and a plurality of second grooves 112. A second groove 112is between two adjacent first grooves 111. In some embodiments, forexample, as shown in FIG. 1, the first grooves 111 and the secondgrooves 112 are arranged in an alternating manner. In some embodiments,the first grooves 111 and the second grooves 112 are arrangedconsecutively in the row direction of the pixel regions 103. The rowdirection is also the direction in which the pixel regions 103 arearranged, as indicated by the arrow R in FIG. 1.

In some embodiments of the present disclosure, as shown in FIGS. 1 and2A, the distance d1 between the bottom of the first groove 111 and thetop surface of the base substrate 100 facing the first groove 111 isgreater than the distance d2 between the top surface of the first pixeldefining layer 102 and the top surface of the base substrate 100. Thetop surface of the first pixel defining layer 102 refers to the surfacethat is on a side of the first pixel defining layer 102 opposite fromthe electrode layer 101. In these embodiments, the first groove 111 doesnot penetrate the second pixel defining layer 104.

In other embodiments of the present disclosure, as shown in FIGS. 2B and2C, the distance d1 between the bottom of the first groove 111 and thetop surface of the base substrate 100 is equal to the distance d2between the top surface of the first pixel defining layer 102. In theseembodiments, the first groove 111 penetrates the second pixel defininglayer 104. The top surface of the first pixel defining layer 102 definesthe bottom of the first groove 111. The production of these embodimentscan be simpler as compared to the production of embodiments where thefirst groove 111 does not penetrate the second pixel defining layer 104.

At least one first opening 113 is formed on a first groove 111. Thefirst opening 113 is formed on a portion of the first groove 111 thatadjacent to a pixel region 103 of a first color, so that the firstopening 113 is configured to connect the first groove 111 to the pixelregion 103 of the first color.

At least one second opening 114 is formed on a second groove 112. Thesecond opening 114 is formed on a portion of the second groove 112adjacent to a pixel region 103 of a second color, so that the secondopening 114 is configured to connect the second groove 112 to the pixelregion 103 of the second color. The second color is different from thefirst color.

The first grooves 111 on adjacent rows of second pixel defining portions104 are arranged so as to be staggered with respect to each other. Thefirst grooves 111 on adjacent rows of second pixel defining portions 104are staggered in the row direction of the pixel regions 103 (forexample, as shown in FIG. 1). The row direction is also the direction inwhich the pixel regions 103 are arranged.

The second groove 114 may be configured in the manner shown in FIG. 1,and more particularly, defined by the second pixel defining portions 104on the two sides of a second groove 112 that are adjacent to the firstgrooves 111. The second pixel defining portions 104 are not present onthe two sides of the second groove 112 that are adjacent to the pixelregions 103.

As shown in FIG. 1, the second grooves 112 in adjacent rows of secondpixel defining portions 104 are staggered in the row direction of thepixel regions 103 (for example, as shown in FIG. 1).

FIG. 4A shows a cross-sectional view of the array substrate illustratedin FIG. 1 along the section line C-C′. FIG. 4B shows a cross-sectionalview of the array substrate exemplified in FIG. 2B along the sectionline C-C′.

As shown in FIGS. 1 to 4, adjacent first groove 111 and second groove112 are separated by the raised portions a, b in the second pixeldefining layer 104. The raised portions a, b are formed in the secondpixel defining layer 104, for example, as shown in FIGS. 4A and 4B. Theraised portions a, b serve as a first wall that separates a secondgroove 112 from adjacent first grooves 111. Further, in the embodimentsillustrated in FIG. 5, the second pixel defining portions 104 arepresent on the two sides of the second groove 112 adjacent to the pixelregions 103, thereby forming a second wall that separates the secondgroove 112 from the adjacent pixel regions 103. As shown in FIG. 5, thesecond opening 114 is formed in the second wall, and has a width w4 inthe row direction that is narrower than a width w3 of the second wall inthe row direction. FIG. 7 shows a cross-sectional view of the arraysubstrate exemplified in FIG. 5 along the section line E-E′. As shown inFIG. 7, the second opening 114 is formed in the second wall separatingthe second groove 112 from the adjacent pixel region 103. The secondgroove 112 is therefore defined by the raise portions a, b in the secondpixel defining layer 104, and the second opening 114. The second opening114 is configured to connect the second groove 112 to pixel regions 103of a color that is different from the color of the pixel regions 103that are connected to the first groove 111 via the first opening 113.

The second pixel defining portions 104 are not present on the two sidesof the second groove 112 adjacent to pixel regions 103, for example, asshown in FIG. 1. This configuration can reduce the amount of materialsnecessary to form the array substrate. The second pixel definingportions 104 are not present in the second groove 112 between twoadjacent rows of pixel regions 103, or on the first pixel defining layer102 between two adjacent rows of pixel regions 103. Light emittingmaterial can be directly deposited into the second groove 112, and canflow into the adjacent pixel regions 103 connected to the second groove112. Even in situations where the light emitting material residuesremain on the first pixel defining layer 102, which is between twoadjacent pixel regions 103, the residues will have minimal or no effectson the light emitting function of the display panel incorporating thearray substrate. The display panel controls light emissions by the lightemitting materials through the electrode layer 101, but any lightemitting material residues that remain on the first pixel defining layer102 would not be in contact with the electrode layer 101, and as such,would not negatively impact the light emissions of the display panel.

FIG. 5 shows a schematic diagram of an array substrate according toanother embodiment of the present disclosure. A difference between theembodiments exemplified in FIG. 1 and FIG. 5 is the structure andconfiguration of the second groove 112.

As shown in FIG. 5, the second pixel defining portions 104 are presenton the two sides of the second groove 112 adjacent to the pixel regions103. The second openings 114 are provided on the two sides of the secondpixel defining portions 104 adjacent to the pixel regions 103. Thesecond openings 114 are configured to connect the second groove 112 topixel regions 103 of a color that is different from the color of thepixel regions 103 that are connected to the first groove 111 via thefirst opening 113.

FIG. 6 shows a cross-sectional view of the array substrate exemplifiedin FIG. 5 along the section line D-D′.

At the position of the second groove 112, the second pixel definingportions 104 are provided on the first pixel defining portions 102. Thesecond groove 112 and the second openings 114 are then formed in thesecond pixel defining portions 104. The second openings 114 are providedon the two sides of the second groove 112 adjacent the pixel regions103.

In the array substrate exemplified in FIGS. 5 and 6, when printing thelight emitting layer in the pixel regions 103 connected to the secondgroove 112, light emitting material is deposited directly into thesecond groove 112, and through the second openings 114, flows into thecorresponding pixel regions 103.

As shown in FIGS. 1 and 5, in one row of the second pixel definingportions 104, a first opening 113 is formed on a side of the firstgroove 111 adjacent to pixel regions 103 of a first color 103B(represented by the downward slanting line pattern in the figures). Thefirst opening 113 is configured to connect the first groove 111 to thepixel regions 103 of the first color. The second opening 114 is formedon a side of the second groove 112 adjacent to pixel regions 103 of asecond color 103A (represented by the diamond pattern in the figures).The second color is different from the first color. In an adjacent rowof the second pixel defining portions 104, a first opening 113 is formedon a side of the first groove 111 adjacent to pixel regions 103 of athird color 103C (represented by the upward slanting line pattern in thefigures). The first opening 113 is configured to connect the firstgroove 111 to the pixel regions 103 of the third color. The first,second, and third colors are different from each other.

More particularly, as shown in FIGS. 1 and 5, in the first row of thesecond pixel defining portions 104, the first groove 111 and pixelregions of the first color 103B are connected via the first opening 113.In the same row of the second pixel defining portions 104, the secondgroove 112 and pixel regions of the second color 103A are connected viathe second opening 114. In the second row of the second pixel definingportions 104, the first groove 111 and pixel regions of the third color103C are connected via the first opening 111, and the second groove 112remains connected to pixel regions of the second color 103A via thesecond opening 114.

The distribution and arrangement of the color pixel regions are notparticularly limited. The color pixel regions may be distributed andarranged in any manner known to a person of ordinary skill in the art tobe suitable within the spirit and scope of the present disclosure. Forexample, in some embodiments, the first color may be red, the secondcolor blue, and the third color green. In some embodiments, the firstcolor may be green, the second color blue, and the third color red. Insome embodiments, the first color may be blue, the second color red, andthe third color green. In some embodiments, the first color may begreen, the second color red, and the third color blue. In someembodiments, the first color may be red, the second color green, and thethird color blue. In some embodiments, the first color may be blue, thesecond color green, and the third color red.

In some embodiments of the present disclosure, the second pixel definingportions 104 are provided on the first pixel defining portions 102 atthe position between two adjacent rows of pixel regions 103. When thelight emitting layer is subsequently printed using inkjet printing, alight emitting material of the first color is directly deposited intothe first groove 111, and flows into the corresponding pixel regions 103that are connected to the first groove 111 via the first opening 113.This allows for simultaneous printing of light emitting layers inadjacent rows of pixel regions, which can in turn improve printresolution and simplify operation of the inkjet printing equipment.

In some embodiments of the present disclosure, first and second grooves111, 112 in odd numbered rows of second pixel defining portions 104 arealigned with each other in the row direction of the pixel regions 103.That is, the first grooves 111 in odd numbered rows of second pixeldefining portions 104 are aligned with each other, and the secondgrooves 112 in odd numbered rows of second pixel defining portions 104are aligned with each other. Conversely, first and second grooves 111,112 in even numbered rows of second pixel defining portions 104 arealigned with each other in the row direction of the pixel regions 103.That is, the first grooves 111 in even numbered rows of second pixeldefining portions 104 are aligned with each other, and the secondgrooves 112 in even numbered rows of second pixel defining portions 104are aligned with each other.

For example, as shown in FIGS. 1 and 5, the first and second grooves111, 1112 in the first and third rows of second pixel defining portions104 are aligned, and the first and second grooves 111, 112 in the secondand fourth rows of second pixel defining portions 104 are aligned.

In other words, first and second grooves 111, 112 in even and oddnumbered rows of second pixel defining portions 104 are staggered withrespect to each other in the row direction of the pixel regions 103.That is, the first grooves 111 in an odd numbered row of second pixeldefining portions 104 are staggered with respect to the first grooves111 in an even numbered row of second pixel defining portions 104.

Likewise, the second grooves 111 in an odd numbered row of second pixeldefining portions 104 are staggered with respect to the second grooves113 in an even numbered row of second pixel defining portions 104.

For example, as shown in FIGS. 1 and 5, the first grooves 111 in thefirst and second rows of second pixel defining portions 104 arestaggered by a distance substantially equal to a width of one pixelregion 103 (in the figures, one pixel region of the second color 103A).The width w1 of a pixel region is measured in the row direction, asshown in FIG. 1. In other words, the first grooves 111 in the first andsecond rows of second pixel defining portions 104 are arranged so as tooverlap by two pixel regions (in the figures, one pixel region of thefirst color 103B and one pixel region of the third color 103C).

The second grooves 112 in the first and second rows of second pixeldefining portions 104 are staggered by a distance substantially equal toa width of two pixel regions 103 (in the figures, one pixel region ofthe first color 103B and one pixel region of the third color 103C). Thewidth w1 of a pixel region is measured in the row direction, as shown inFIG. 1.

As shown in FIGS. 1 and 5, the number of pixel regions of the firstcolor 103B that are connected to the first groove 111 in the first rowof second pixel defining portions 104 is four (4), and the number ofpixel regions of the third color 103C that are connected to the firstgrooves 111 in the second row of second pixel defining portions 104 isfour (4). The number of pixel regions of the second color 103A that areconnected to the second grooves 111 in any given row of second pixeldefining portions 104 is two (2).

During inkjet printing, each first groove 111 is aligned with a nozzleon the inkjet printer, and each second groove 112 is aligned withanother nozzle. When the nozzle deposits light emitting material havingthe first color in the first groove 111, the configuration of the firstopenings 113 allows the light emitting material to flow simultaneouslyinto four (4) pixel regions 103B. Similarly, when the nozzle depositslight emitting material having the third color in the first groove 111in a different row of second pixel defining portions 104, theconfiguration of the first openings 113 allows the light emittingmaterial to flow simultaneously into four (4) pixel regions 103C. Whenthe nozzle deposits light emitting material having the second color inthe second groove 112, the configuration of the second openings 114allows the light emitting material to flow simultaneously into two (2)pixel regions 103A.

In the embodiment illustrated in FIG. 1, since the second pixel definingportions 104 are not present on the sides of the second groove 112adjacent to the pixel regions 103, a printer nozzle having a largervolume may be used to deposit light emitting material having the secondcolor simultaneously in both the second groove 112 and the two pixelregions 103A connected to the second grooves 112. The lighting emittingmaterial can distribute evenly through the second openings 114, so thateven if light emitting material residues remain in the second groove112, the residues would not affect the light emission of the displaypanel incorporating the array substrate. Conversely, in the embodimentillustrated in FIG. 5, since the second pixel defining portions 104 arepresent on the sides of the second groove 112 adjacent to the pixelregions 103, light emitting material having the second color isdeposited in the second groove 112. The light emitting material thenflows into the pixel regions of the second color 103A via the secondopenings 114.

Conventionally, an inkjet printing apparatus is equipped with aplurality of nozzles, each of which is aligned with a row of pixelregions, so that the number of nozzles required is usually equal to thenumber of rows of pixel regions. During printing, the nozzles are movedas necessary to deposit ink in each of the pixel regions. Products withhigh PPI (pixels per inch) requires high pixel density, so that theinkjet printing apparatus used to produce such products must be equippedwith nozzles that are also arranged in high density. The design,construction, and operation of such an inkjet printing apparatus arenecessarily complex. In contrast, the present disclosure advantageouslyreduces the number of nozzles needed for inkjet printing, and in sodoing, greatly simplifies the construction and operation of anynecessary printing apparatus.

For example, embodiments of the present disclosure can reduce the numberof nozzles necessary to print pixel regions corresponding to the firstcolor 103B by ¼, the number of nozzles necessary to print pixel regionscorresponding to the first color 103C by ¼, and the number of nozzlesnecessary to print pixel regions corresponding to the second color 103Aby ½. The number of nozzles needed to fill all the pixel regions 103 isconsiderably smaller than in conventional inkjet printing techniques,and as a result, the construction and operation of any inkjet printingapparatus employed to produce an array substrate according to thepresent disclosure can be greatly simplified.

In addition, since light emitting layers can be formed in four pixelregions 103 simultaneously with a single deposit of the light emittingmaterial in the first groove 111, the printing process itself can begreatly simplified. The process is made all the more simpler by allowinga single deposit of light emitting material in the second groove 112 toform light emitting layers simultaneously in two pixel regions 103.

In some embodiments of the present disclosure, the first grooves 111 mayhave a larger surface area than the second grooves 112, so as to improveprint precision. In some embodiments, a width of the first groove 111 isabout five times larger than a width of the second groove 112. The widthof the first and second groove 111, 112 is measured in the rowdirection. For example, the width of a first groove 111 is shown as w2in FIG. 1, and the width of a second groove 112 (not shown in thefigures) would be measured in the same direction. Meanwhile, theconfiguration of the second grooves 112 according to the presentdisclosure, which allows a single deposit of light emitting material inthe second groove 112 to form light emitting layers simultaneously intwo pixel regions 103, can improve print resolution.

In some embodiments of the present disclosure, the first pixel defininglayer 102 and the second pixel defining layer 104 are formedsimultaneously. That is, the first pixel defining layer 102 and thesecond pixel defining layer 104 are formed in a single patterning step.However, in some embodiments of the present disclosure, the first pixeldefining layer 102 and the second pixel defining layer 104 are formed ina double-patterning process, where a first patterning step forms thefirst pixel defining layer 102, and a second patterning step forms thesecond pixel defining layer 104 on the first pixel defining layer 102.

Embodiments of the present disclosure utilize a double-layer structurefor the pixel defining layers. A first pixel defining layer comprising aplurality of pixel regions is provided on a substrate. A second pixeldefining layer is formed on the first pixel defining layer at a positionbetween two adjacent rows of pixel regions. The second pixel defininglayer has a plurality of first grooves and a plurality of secondgrooves. The first grooves and the second grooves are arranged in analternating manner. A first opening is provided on at least one portionof a first groove adjacent to a pixel region of a first color. The firstopening is configured to connect a plurality of pixel regions of thefirst color with the first groove. A second opening is provided on atleast one portion of a second groove adjacent to a pixel region of asecond color. The second opening is configured to connect a plurality ofpixel regions of the second color with the second groove. The firstcolor and the second color are different. When using inkjet printing toform the array substrate, light emitting materials are dispensed by theprinter nozzles directly into the first and second grooves. Moreparticularly, a light emitting material of the first color is directlydeposited into the first groove, and the flows into the correspondingpixel regions that are connected to the first groove via the firstopening. A light emitting material of the second color is deposited intothe second groove, and flows into the corresponding pixel regions thatare connected to the second groove via the second opening. Thedouble-layer structure of the pixel defining layers makes is possible tosimultaneously print light emitting layers in adjacent rows of pixelregions. An advantage of the embodiments of the present disclosure isthat, without making extensive, wholesale modifications to existinginkjet printing equipment, print resolution can be significantlyimproved, and the ease of operating the inkjet printing equipment can befacilitated.

The present disclosure also provides a display panel. The display panelmay comprise an array substrate as described above, for example,according to one or more of the embodiments exemplified in FIGS. 1 to 6.

The display panel according to the present disclosure comprises a lightemitting layer formed in each pixel region 103. Using inkjet printing,first light emitting layers are formed in the pixel regions of the firstcolor 103B, second light emitting layers in the pixel regions of thesecond color 103A, and third light emitting layers in the pixel regionsof the third color 103C.

The display panel according to the present disclosure incorporates anarray substrate having a double-layer pixel defining layer structure.The double-layer structure of the pixel defining layers makes ispossible to simultaneously print light emitting layers in multiple pixelregions, so that without requiring extensive, expensive, and wholesalemodifications to existing inkjet printing equipment, remarkableimprovements could be obtained in print resolution and the operation ofthe inkjet printing equipment could be greatly simplified.

The present disclosure also provides a method of fabricating the arraysubstrate. FIG. 8 shows a flow diagram of a method of fabricating anarray substrate according to an embodiment of the present disclosure.The method comprises the following steps.

In step 801, an electrode layer is formed on the base substrate. Theelectrode layer 101 is generally an anode layer, and may be formed ofany suitable material (for example, indium tin oxide (ITO)) and by anysuitable means known to a person of ordinary skill in the art. There areno particular limitations on the base substrate 100, which may be formedof any suitable material known to a person of ordinary skill in the art.For example, the base substrate may be a glass substrate, a quartzsubstrate, a metal substrate, a resin substrate, and the like.

In step 802, a first pixel defining layer is formed on the electrodelayer. A first pixel defining film is deposited on the electrode layer101, and then the first pixel defining film is patterned to form thefirst pixel defining layer 102. The first pixel defining layer 102demarcates the base substrate 100 into a plurality of pixel regions 103arranged in a plurality of rows.

In step 803, a second pixel defining layer is formed on the first pixeldefining layer at a position between two adjacent rows of pixel regions.The second pixel defining layer has a plurality of first grooves and aplurality of second grooves. A second groove is between two adjacentfirst grooves. There are no particular limitations on the process offorming the first grooves. For example, the first grooves 111 may beformed by an etching process (for example, dry etching or wet etching),or by any other suitable means known to a person of ordinary skill inthe art.

To form the second pixel defining layer, a second pixel defining film isdeposited on the first pixel defining layer 102, and then the secondpixel defining film is patterned to form the second pixel defining layer104. A double-patterning process is described above for forming thefirst and second pixel defining layers 102, 104. However, in someembodiments of the present disclosure, the first pixel defining layer102 and the second pixel defining layer 104 may be formed simultaneouslyin a single patterning step, so as to simplify the production process.For example, a first pixel defining film is deposited on the firstelectrode layer, followed by the depositing of a second pixel definingfilm on the first pixel defining film. The first pixel defining film andthe second pixel defining film are patterned simultaneously to form thefirst pixel defining layer and the second pixel defining layer,respectively.

In step 804, at least one first opening is formed in the first groove.At least one first opening 113 is formed on a portion of the firstgroove 111 adjacent to a pixel region 103 of a first color. The firstopening 113 is configured to connect the first groove 111 to the pixelregions 103 of the first color. The first grooves 111 on adjacent rowsof second pixel defining layers 104 are arranged so as to be staggeredwith respect to each other, and more particularly, the first grooves 111on adjacent rows of second pixel defining layers 104 are staggered inthe row direction of the pixel regions 103.

In step 805, at least one second opening is formed in the second groove.At least one second opening is formed in a portion of the second grooveadjacent to a pixel region of a second color, the second color beingdifferent from the first color of the pixel regions adjacent to thefirst groove. The second opening 114 is configured to connect the secondgroove 111 to the pixel regions 103 of the second color.

Embodiments of the present disclosure utilize a double-layer structurefor the pixel defining layers. A first pixel defining layer comprising aplurality of pixel regions is provided on a substrate. A second pixeldefining layer is formed on the first pixel defining layer at a positionbetween two adjacent rows of pixel regions. The second pixel defininglayer has a plurality of first grooves and a plurality of secondgrooves. The first grooves and the second grooves are arranged in analternating manner. A first opening is provided on at least one portionof a first groove adjacent to a pixel region of a first color. The firstopening is configured to connect a plurality of pixel regions of thefirst color with the first groove. A second opening is provided on atleast one portion of a second groove adjacent to a pixel region of asecond color. The second opening is configured to connect a plurality ofpixel regions of the second color with the second groove. The firstcolor and the second color are different. When using inkjet printing toform the array substrate, light emitting materials are dispensed by theprinter nozzles directly into the first and second grooves. Moreparticularly, a light emitting material of the first color is directlydeposited into the first groove, and the flows into the correspondingpixel regions that are connected to the first groove via the firstopening. A light emitting material of the second color is deposited intothe second groove, and flows into the corresponding pixel regions thatare connected to the second groove via the second opening. Thedouble-layer structure of the pixel defining layers makes is possible tosimultaneously print light emitting layers in adjacent rows of pixelregions. An advantage of the embodiments of the present disclosure isthat, without making extensive, wholesale modifications to existinginkjet printing equipment, print resolution can be significantlyimproved, and the ease of operating the inkjet printing equipment can befacilitated.

The present disclosure also provides a method of fabricating a displaypanel incorporating an array substrate described herein. FIG. 9 shows aflow diagram of a method of fabricating a display panel according to anembodiment of the present disclosure. The method comprises the followingsteps.

In step 901, an array substrate as described herein is provided.

In step 902, a light emitting material having a first color is depositedin first grooves connected to corresponding pixel regions of the firstcolor. The light emitting material deposited in the first grooves 111flows into the corresponding pixel regions via the first openings 113that are formed in the first grooves 111 to connect the first grooves111 with those pixel regions.

The light emitting material may be a liquid organic material. The lightemitting material in the pixel regions 103 dries to form the lightemitting layer. The light emitting material may also be a liquidinorganic material, for example, quantum dots.

The pixel regions 103 are formed with identical, or substantiallysimilar, properties (including surface properties), so that the lightemitting material self-levels under the effect of surface tension andbecomes uniformly distributed in each pixel region. As the lightemitting material dries, the resulting light emitting layer is alsouniformly distributed in each pixel region. Even if there are slightdifferences in the distribution of the light emitting layer in the pixelregions, the differences may be corrected through the first pixeldefining layer.

The first grooves 111 in odd numbered rows of second pixel defininglayers 104 are connected to pixel regions of the first color 103B, andthe first grooves 111 in even numbered rows of second pixel defininglayers 104 are connected to pixel regions of the third color 103C. Lightemitting material having the first color is dripped in the first grooves111 in odd numbered rows of second pixel defining layers 104, flowsthrough first openings 113 in the first grooves into the correspondingpixel regions 103B, and dries to form light emitting layers that emitlight of the first color. Light emitting material having the third coloris dripped in the first grooves 111 in even numbered rows of secondpixel defining layers 104, flows through first openings 113 in the firstgrooves into the corresponding pixel regions 103C, and dries to formlight emitting layers that emit light of the third color.

In step 903, a light emitting material having a second color isdeposited in second grooves connected to corresponding pixel regions ofthe second color. The light emitting material dripped in the secondgrooves 112 flows into the corresponding pixel regions via the secondopenings 114 in the second grooves 112 to connect the second grooves 112with those pixel regions. Light emitting material dripped in the secondgrooves 112 have a different color from that of the light emittingmaterial deposited in the first grooves 111.

In the embodiment illustrated in FIG. 1, since the second pixel defininglayer 104 is not present on a side of the second groove 112 adjacent tothe pixel regions 103, a printer nozzle having a larger volume may beused to dispense light emitting material having the second colorsimultaneously in both the second groove 112 and the two pixel regions103A connected to the second grooves 112. The light emitting materialwill dry to form the corresponding light emitting layer.

Conversely, in the embodiment illustrated in FIG. 5, since the secondpixel defining layer 104 is present on a side of the second groove 112adjacent to the pixel regions 103, light emitting material having thesecond color is deposited in the second groove 112. The light emittingmaterial then flows into the pixel regions of the second color 103A viathe second openings 114.

The order in which steps 902 and 903 are performed is not limited tothat described herein, and may be adjusted according to the requirementsof the production process.

A person of ordinary skill in the art would readily appreciate that theconfiguration of a display panel is not limited to the embodiments ofthe present disclosure, and a display panel may include any additionalcomponents that are typically found in a display panel and/or that areprovided according to any particular purpose for which the display panelis intended.

In a display panel incorporating an array substrate of the presentdisclosure, a light emitting material of the first color is directlydripped into the first groove, and flows into the corresponding pixelregions that are connected to the first groove via a first opening. Alight emitting material of the second color is dripped into the secondgroove, and flows into the corresponding pixel regions that areconnected to the second groove via a second opening. By adjusting thestructure of the pixel defining layers, the present disclosure makes ispossible to simultaneously print light emitting layers in multiple pixelregions, so that without requiring extensive modifications to existinginkjet printing equipment, remarkable improvements could be obtained inprint resolution and the operation of the inkjet printing equipmentcould be greatly simplified.

It should be appreciated that changes could be made to the embodimentsdescribed above without departing from the inventive concepts thereof.It should be understood, therefore, that this invention is not limitedto the particular embodiments disclosed, but it is intended to covermodifications within the spirit and scope of the present invention asdefined by the appended claims.

What is claimed is:
 1. An array substrate, comprising: a base substrate;an electrode layer on the base substrate; a first pixel defining layeron the electrode layer defining a plurality of pixel regions arranged inan array of at least a first color and a second color, the second colorbeing different from the first color; and a second pixel defining layeron the first pixel defining layer having a plurality of first groovesand a plurality of second grooves alternately arranged between twoadjacent rows of pixel regions, wherein: each of the plurality of firstgrooves has at least one first opening connecting the each of theplurality of first grooves to a pixel region of the first color; andeach of the plurality of second grooves has at least one second openingconnecting the each of the plurality of second grooves to a pixel regionof the second color.
 2. The array substrate according to claim 1,wherein the plurality of first grooves in two adjacent rows arestaggered with respect to each other along a row direction.
 3. The arraysubstrate according to claim 2, wherein the plurality of first groovesin two adjacent rows are staggered by a distance substantially equal toa width of one pixel region along the row direction.
 4. The arraysubstrate according to claim 1, wherein the plurality of second groovesin two adjacent rows are staggered with respect to each other along arow direction.
 5. The array substrate according to claim 4, wherein theplurality of second grooves in two adjacent rows are staggered by adistance substantially equal to a width of two pixel regions along therow direction.
 6. The array substrate according to claim 1, wherein thesecond pixel defining layer further comprises a plurality of raisedportions, each of the plurality of raised portions being positioned toseparate each of the plurality of first grooves from an adjacent secondgroove.
 7. The array substrate according to claim 2, wherein: the firstcolor comprises two different colors, the plurality of first grooves intwo adjacent rows are connected to the two different colors.
 8. Thearray substrate according to claim 1, wherein a combined thickness ofthe first pixel defining layer and the second pixel defining layer is inthe range of about 1.2 μm to about 2.5 μm.
 9. The array substrateaccording to claim 1, wherein a combined thickness of the first pixeldefining layer and the second pixel defining layer is in the range ofabout 1.5 μm to about 5 μm.
 10. The array substrate according to claim1, wherein each of the plurality of first grooves does not penetrate thesecond pixel defining layer.
 11. The array substrate according to claim1, wherein each of the plurality of first grooves penetrates the secondpixel defining layer.
 12. The array substrate according to claim 1,wherein a width of each of the plurality of first grooves in a rowdirection is about five times larger than a width of each of theplurality of second grooves in the row direction.
 13. The arraysubstrate according to claim 1, wherein: each of the plurality of secondgrooves comprises a first wall separating the second groove from anadjacent first groove, and a second wall separating the second groovefrom an adjacent pixel region of the second color, and the at least onesecond opening is formed m the second wall, and has a width in a rowdirection that is smaller than a width of the second wall in the rowdirection.
 14. A display panel, comprising: the array substrateaccording to claim 1; and a light-emitting layer formed in the pluralityof pixel regions.
 15. A method of fabricating the array substrateaccording to claim 1, the method comprising: forming the electrode layeron the base substrate; forming the first pixel defining layer on theelectrode layer; and forming the second pixel defining layer on thefirst pixel defining layer, wherein the second pixel defining layer hasthe plurality of first grooves and the plurality of second grooves. 16.The method according to claim 15, wherein: the forming of the firstpixel defining layer comprises: depositing a first pixel defining filmon the electrode layer; and patterning the first pixel defining filminto the first pixel defining layer, and the forming of the second pixeldefining layer comprises: depositing a second pixel defining film on thefirst pixel defining layer; and patterning the second pixel definingfilm into the second pixel defining layer.
 17. The method according toclaim 15, wherein: the first pixel defining layer and the second pixeldefining layer are formed in a single patterning step, and the singlepatterning step comprises: depositing a first pixel defining film on theelectrode layer; depositing a second pixel defining film on the firstpixel defining film; and patterning the first pixel defining film andthe second pixel defining film simultaneously to form the first pixeldefining layer and the second pixel defining layer.
 18. A method offabricating the display panel according to claim 14, the methodcomprising: providing the array substrate; dripping a first lightemitting material into the plurality of first grooves; and dripping asecond light emitting material into the plurality of second grooves.